CASCADABILITY AND FUNCTIONALITY OF ALL-OPTICAL LOW-BIREFRINGENT NONLINEAR-OPTICAL LOOP MIRROR - EXPERIMENTAL DEMONSTRATION

We verify both experimentally and theoretically the cascadability and the Boolean complete functionality of the low-birefringent nonlinear o ptical loop mirror (low-bi NOLM) operating with all inputs at the same wavelength. We achieve a low switching energy by using a low-birefrin gent (Delta n similar to 3.5 x 10(-6)), polarization maintaining fiber to achieve a longer interaction length between two orthogonally polar ized pulses. We experimentally demonstrate switching in the cascaded o peration of two low-bi NOLM's using picosecond pulses from an erbium-d oped fiber laser. This has the potential to have a bit rate of 100 Gb/ s. After the two cascaded low-hi NOLM's, the performance is a peak swi tching contrast of 36:1 and a timing window of 1.7 pulse widths with a switching energy of 9 pJ. In addition, we demonstrate the AND and the XOR/NOT operations with the low-bi NOLM showing Boolean completeness. The AND operation has a switching contrast of 84.5:1, and the XOR/NOT has a switching contrast of 11.5:1. Finally, we study the gate numeri cally and find good agreement between experiments and simulations. (C) 1997 Optical Society of America.